1. Field of the Invention
The present invention relates to an indwelling needle assembly usable for introducing a catheter into a vascular system of a patient at a time of infusion.
2. Description of the Related Art
A catheter is a thin tubular medical device or any device including a thin tube used to permit infusion or withdrawal of fluid into a vascular system or any cavity of a patient's body. To introduce such a catheter into a vascular system of a patient, a needle assembly with a needle slidably fitted in the catheter is frequently used. A medical personnel pierces a patient's body with the needle along with the catheter. Thereafter the needle may be extracted but the catheter is left indwelled in the patient's body. The catheter is connected to an infusion device and thereby comes to be available for infusion. Some needle assemblies are comprised of telescopically extensible sleeves as a safety guard for covering the needles so as to prevent accidental sticking.